Sustainability

Banking on the motors

By Philippa Martin-King

When the going gets tough, a customary fiscal reaction of many states is to print additional national currency. As the millions of fresh banknotes roll off the printing press, how many of us stop to think of the many processes involved in their manufacture? Or of the number of efficiently run motors required to produce the simple piece of paper that represents so much, both culturally and financially? A banknote has that dual role. Graphically, it depicts national pride, history. Financially, through its many security printing and manufacturing technologies, it ensures that the note retains its face value. Each of the manufacturing efforts involved is wholly dependent on the efficiency and reliability of its own machinery.

Industry still consumes over a third of the world's total electricity

Industry is one of the areas that has made the greatest efforts to curb use of electricity. Its share of world electricity consumption fell from 53,4 % in 1973 to 41,7 % in 2008. Yet 2010 figures show that industry is still consuming over a third of the world's total electricity requirement, with some sixty percent of that powering electric motors. The top four of the greatest energy users are the chemical, bulk refining, paper and mining industries. All four industries form an essential part of the banknote manufacturing chain in supplying pigments, inks, resins, high-technology chemistry and substrates for printed currencies. It follows that if the efficiency of the motors used in the manufacturing process can be enhanced even fractionally, then there are substantial economies to be made, both in terms of manufacturing costs and also of CO2 emissions.

An IEC International Standard, IEC 60034-30, Rotating electrical machines - Part 30: Efficiency classes of single-speed, three-phase, cage-induction motors (IE-code), specifying efficiency classes for relevant 50 Hz and 60 Hz motors, has been adopted by leading manufacturers of industrial motors around the world. This IEC International Standard classifies motors into three levels depending on how efficiently they convert electricity into mechanical energy: IE1 is the base standard for efficiency, IE2 stands for high efficiency and IE3 for premium efficiency. The standard also mentions a future level of products above IE3, not yet commercially available, which will go by the name IE4 super premium efficiency.

The classification system has stimulated competition among motor manufacturers and generated massive technology improvements. Although IEC International Standards are voluntary, the EU (European Union) has adopted the IEC classification system and issued a Commission Regulation (EC) 640/2009, which came into effect on 16 June 2011. Now, only motors that meet or exceed IE2 energy efficiency levels are allowed to be sold and installed in the EU.

When you next take a banknote out of your wallet, take a second to admire the final product of so many steps of machining and think of all those finely tuned motors that provide the reassurance automatically associated with currency.

Philippa Martin-King,
Managing Editor, e-tech

In a second stage, from January 2015, all motors will need to reach IE3 efficiency levels (or IE2 combined with variable speed drives). Generally referred to as EU MEPS (Minimum Energy Performance Standard), the requirement covers most two, four and six pole motors in the power range of 0,75 to 375 kW (kilowatt) for alternating current (AC) power supply frequencies of 50 and 60 Hz (Hertz).

The ZVEH (Zentralverband der Deutschen Elektro- und Informationstechnischen Handwerke, the central association of the German electrical and information technology industries) has calculated that this regulation will affect some 30 million old industrial motors in Europe alone. As they are gradually replaced, the resulting energy savings are estimated to be roughly 5,5 billion kilowatt hours of electricity each year with a corresponding reduction of 3,4 million tons of CO2. Proof that energy efficiency measures can be profitable for the environment and for the investor is the fact that investment replacement payback can be achieved in one to three years (and in under one year when combined with variable speed controls).

Other countries not affected by EU MEPS, which covers only European Union markets, have already implemented similar energy efficiency schemes and are active participants in the IEC. They include Australia, China, Brazil and Canada. In the US, the NEMA (National Electrical Manufacturers Association) motor energy efficiency programme follows closely the IEC energy classifications. For instance, the NEMA Premium is identical to IE3 and NEMA motors have to be tested in accordance with the IEC testing protocol contained in IEC 60034-2-1.

So when you next take a banknote out of your wallet, take a second to admire the final product of so many steps of machining. From the substrate, made of strong pure cotton to withstand all the wear and tear of being handled multiple times in particularly dry or humid or salty climates, to the elements printed using intaglio or silkscreen methods with their exceptional colour-changing Optically Variable Ink, think of all those motors finely tuned and set up and providing the reassurance that is automatically associated with currency.

Turning motors to produce currency

Historically, banknotes involved a number of manual processes. Today, all stages of manufacturing are controlled by motors that run the sophisticated machinery.

Substrate – engineered to perfection

Most banknotes are made of cotton, rolled and processed to a particular thickness and tolerance, with additives that give them the colour, and visual security elements such as threads and watermarks, that each citizen associates with his or her currency. Some notes are printed on plastic substrates that have their own particular needs as far as ink adherence is concerned.

Pigments – grinding with finesse

All inks contain pigments which provide them with their unique colour. Pigments can be made of a variety of organic or inorganic materials, each with their own specific properties. They need to be ground to a fine powder with the utmost precision and care, to ensure that they will bind accurately with the resins and other chemical substances used.

Inks – crucial manufacturing for high security

There are inks for every printing process, whether offset, intaglio, silkscreen, letterpress, serigraphy, flexography or gravure. Each has to be carefully manufactured with the correct mixture of pigment and binding substances that correspond to the printing method and to ensure its successful transfer from press to substrate. The binding resinous substance is particularly crucial: it has to be manufactured taking account both of the printing process, and the range of use that the note may encounter later on in its everyday life.

One particularly notable ink is OVI® (Optically Variable Ink). Its colour-shifting properties make it an excellent and highly visible anti-counterfeiting measure. Manufactured in Switzerland, it shows one colour when viewed at arm’s length from waist height and another when looked at close-to at eye level. That enables it to provide attractive colourful design features and makes it particularly good as a security feature, since a colour photocopier or scanner is incapable of reproducing both colours. As a result, forged notes can be detected easily. OVI can be applied either using silkscreen or intaglio processes, which opens up endless possibilities from the point of view of design.

Offset – rolling off the dots with applied chemistry

The classic printing technology consists of a series of dots that, to the naked eye, combine to give the impression of blocks of colour. It uses chemical technology that makes ink adhere to the various parts of the different plates from which it is transferred to the substrate, or, using the opposite approach, prevents the ink from transferring from the rollers that come into contact with the plate, so as to create blank areas on the paper. Each colour is dealt with separately, using a different plate, although certain specialist banknote printers have developed special techniques to apply more than one colour at a time.

Intaglio – machine-engraving and applied pressure and heat

The intaglio process is the one that supplies the typical tactile effect so often associated with banknotes. The raised effect is due to the thickness of the ink that is left on the substrate on which it is printed. Originally intaglio printing used a hand-engraved plate as the basis for its design. Nowadays these are produced by motor-driven machines. The viscous ink is spread on the engraving where it sinks into every line and hollow of the design. Having wiped the plate's surface, the only ink left is in the etched part. To transfer it to the substrate requires significant pressure and high temperatures. A roller presses the substrate into the recesses of the plate, leaving a positive, raised image of ink.

Silkscreen and its relevant drying equipment

Silkscreen printing now no longer uses silk to create the printed designs, but a mesh of other fibres through which the inks are pushed in a sieve-like manner. Parts of the mesh are blanked out so that the ink is only transferred to the substrate where the screen is left open. Silkscreen printing needs a particularly efficient drying system. That calls on yet another set of motors to operate the heated ventilation and corresponding airing systems.

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